首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   399篇
  免费   29篇
  国内免费   38篇
安全科学   33篇
废物处理   15篇
环保管理   119篇
综合类   170篇
基础理论   22篇
环境理论   2篇
污染及防治   15篇
评价与监测   8篇
社会与环境   75篇
灾害及防治   7篇
  2023年   6篇
  2022年   7篇
  2021年   7篇
  2020年   10篇
  2019年   16篇
  2018年   12篇
  2017年   25篇
  2016年   20篇
  2015年   15篇
  2014年   12篇
  2013年   27篇
  2012年   31篇
  2011年   27篇
  2010年   17篇
  2009年   21篇
  2008年   16篇
  2007年   32篇
  2006年   31篇
  2005年   13篇
  2004年   14篇
  2003年   13篇
  2002年   20篇
  2001年   6篇
  2000年   9篇
  1999年   11篇
  1998年   6篇
  1997年   5篇
  1996年   4篇
  1995年   4篇
  1994年   2篇
  1993年   2篇
  1992年   2篇
  1991年   1篇
  1990年   3篇
  1988年   2篇
  1986年   1篇
  1984年   2篇
  1983年   1篇
  1982年   3篇
  1981年   2篇
  1980年   2篇
  1979年   2篇
  1978年   1篇
  1977年   1篇
  1974年   1篇
  1973年   1篇
排序方式: 共有466条查询结果,搜索用时 515 毫秒
421.
State governments in the United States have adopted a number of policies to encourage the production of electricity from “green” energy sources. While these state-level policies have been shown to stimulate green electricity development, the rate at which such policies have been adopted by the states differs significantly. This paper examines the potential influence of a state's particular social, political, and economic interests on its propensity to adopt green electricity policies. We use an empirical model that combines various social, political and economic indicators as explanatory variables of a state's likelihood to adopt four specific green electricity policies: renewable portfolio standards, net metering rules, public benefits funds, and generation disclosure rules. Using binary logistics regressions, the results suggest that social interests, measured by the level of income, the level of education, and the degree of participation in environmental lobbying groups, are positively linked to the adoption of green electricity policies. Similarly, political interests as measured by the pro-environment voting by states’ representatives in the U.S. Congress, also play a positive role in the adoption of such policies.  相似文献   
422.
Determining adequate baselinesis a major methodological problem whenquantifying emissions reductions achievedwith the project-based flexibilitymechanisms. Possible methodologies forbaseline setting may be classified intomulti-project and project-specificapproaches. While multi-project approachesprovide baselines for a series of typicalprojects within a certain geographicregion, a sector, or a load range,project-specific (orproject-by-project/single-project)approaches only cover one specific project.Project-by-project baseline approaches havebeen tested extensively within theActivities Implemented Jointly (AIJ) pilotphase; multi-project methodologies, on theother hand, have only rarely been applieddue to the (perceived) political andeconomic complexity of the issue, whichmakes the process of introducingstandardised baselines a very sensitivetask. In particular, there is a lack ofmulti-project baseline approaches takingadvantage of optimising computer modelswithin the electricity sector, even thoughother fields of research have made use ofsuch models quite successfully in the past.Experiences made in the PROBASE projectwith the calculation of standardised,aggregated multi-project baselines forJI/CDM projects using optimising energysystem models are illustrated in this paperfor South Africa, Russia, and Indonesia.Increased transparency and credibility ofstandardised approaches along withpotentially lower transaction costs areidentified as the main arguments for theiruse and further development. In addition,the text gives recommendations wheremodel-based baseline standardisation canpreferentially be applied.  相似文献   
423.
会计信息失真是当前严重影响社会经济正常秩序的一个突出问题.会计信息失真的表现形式是多样化的,因而导致会计信息失真的原因也是多种多样的,而且比较复杂,其原因并非正式约束机制的软化及正式约束机制的滞后和缺乏,为治理会计信息失真,必须从制度方面和技术方面两方面共同努力.  相似文献   
424.
本文建立了新疆生产建设兵团农垦城镇类、等、级及基准地价的城镇土地等级体系,为兵团农垦城镇不同层次的土地管理提供了科学依据,对深化我国土地有偿使用制度改革,建立健全合理的土地市场,实现土地资源资产化等具有较好的理论和实践探索意义。  相似文献   
425.
利用垃圾填埋沼气发电走垃圾资源化道路   总被引:2,自引:0,他引:2  
李丽丹  钟甦 《环境科技》2006,19(Z2):136-137
针对我国垃圾产生量大,以填埋处理方式为主的状况,介绍了垃圾填埋沼气发电的原理、技术和国内外现状等,提出要利用垃圾填埋产生的沼气进行发电使城市垃圾化害为利,变废为宝,实现垃圾资源化。  相似文献   
426.
For projects under the UNFCCC Kyoto Protocol Clean Development Mechanism (CDM), a baseline has to be set to allow calculation of the greenhouse gas emissions reductions achieved. An important obstacle to CDM project development is the lack of data for baseline definition; often project developers do not have access to data and therefore incur high transaction costs to collect them. The government of Vietnam has set up all necessary institutions for CDM, wants to promote CDM projects and thus is interested to reduce transaction costs. We calculate emission factors of the Vietnam electricity grid according to the rules defined by the CDM Executive Board for small scale projects and for large renewable electricity generation projects. The emission factors lie between 365 and 899 g CO2/kWh depending on the specification. The weighted operating and build margin reaches 600 g for 2003, while grid average reaches 399 g. Using three-year averages, a combined build and operating margin of 705 g is calculated. We hope that these data facilitate CDM project development in the electricity supply and energy efficiency improvement in Vietnam.  相似文献   
427.
Read, Sims and Adams (2001) detailed a case study for bio-energy implementation in a notional small Pacific Island and elaborated a theoretical model for assessing and simulating the socio-economic impacts of a particular bio-energy system designed to produce an exportable liquid fuel along with rural electricity supplies. An important conclusion was that there is no silver-bullet ‘one size fits all’ bio-energy system suited to all situations. Moreover, a system appropriate at one place and time may become obsolete with exogenous technological advance and/or as a community advances down its own development pathway. In order to understand how these issues interact in practice, a selected set of implementation projects is reviewed highlighting scale, capacity, community, technology, governmental policy and the concept of critical mass, as factors that are central to the successful development of the bioenergy sector. Through this evaluation, it is shown that: 1.A significant biomass supply resource base often exists locally in the form of agricultural and forestry residues on which modern bioenergy programmes could be initiated. The use of biomass energy flow charts are an important tool for evaluating the potential of local and national resources. 2. Without an integrated multi-disciplinary, multi-sector and whole-systems approach to the implementation of bioenergy schemes, long term success is likely to remain elusive. 3. There is a requirement at the national level for a coordinated approach with strong policy signals that overcome perverse and practical obstacles.  相似文献   
428.
城市水资源供需系统优化分析   总被引:10,自引:1,他引:10  
运用系统动力学的方法,研究了城市水资源供需系统的优化分析。系统中主要包括了人口、工业生产、水资源供应和污染等4个状态变量,其中总可供水量是系统的控制变量;得出水价和水污染整治投资比例是两个关键因素,系统运行结果表明,只有二者相互协调,共同发挥作用,才能保证城市水资源的可持续利用,缺一不可。论文以长春市为例,分析了城市水资源供需系统的动态变化,并提出了解决水资源短缺以及水体污染的控制方案。  相似文献   
429.
本文通过对数字时间序列分析中最大熵谱法的研究,给出了分辨率比传统谱方法高得多的功率谱,针对扬沸过程燃烧噪声的谱特性,建立了扬沸前兆噪声的工程识别模型。本文第二部分讨论了该模型的建立方法,并在实验中得到验证。  相似文献   
430.
在喷嘴前设置感应环,并在喷嘴与感应环间施加电压,能够获得带电水雾。而水雾带电量的大小与感应环施加电压呈线性关系,与喷嘴距感应环距离呈抛物线关系。带电水雾比普通水雾净化效率高近20%,且带电水雾对微细粉尘的捕集效率提高。  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号